“Of course, they’re probably stretching a point when they say I’m to be here only three or four hours,” reflected the boy.  “Yet, now I’m here, I imagine I’ll have to remain here until they’re pleased to let me out.  But—­will I, though?”

Overhead, at that moment, sounded the tinkle of a mandolin.  It came, apparently, from the room nearer the front door.  The two foreigners began to hum softly to the accompaniment of their instrument.

“May-be it was a lucky thing it never occurred to the pair to search me,” murmured the submarine boy.  “Probably they wouldn’t have left this box of matches in my possession.”

Lighting one of the matches, Jack began to explore.  The cellar was much like any other, and wholly empty.  On each side was a little, low window, probably not large enough for the submarine boy to crawl through.  Even at that the openings had been bricked up and looked as though they would resist a long assault.

At the rear of the cellar were steps, leading up to a stout-looking bulkhead.  It was padlocked, on the under side, with stout hasp and staples.

“Nothing doing here, either,” muttered Jack.  “Yet—­hold on—­blazes!”

Almost feverishly he felt in an inner pocket.  It was there—­a case containing seven or eight small, fine saws and other tools often employed by machinists in constructing small devices or models.  He had been using some of the instruments on the boat that afternoon.

“Wow!” sputtered the submarine boy, joyously.  “And again—­some more wow!”

Lighting another match, carefully selecting his saw, and then lighting still another match, he took a look at the padlock, trying to find some portion of the ring where the metal was more slender.  The saw was intended for use on metals.  After he had made a sufficient notch in the ring, young Benson was able to work, much of the time, in darkness.

“Blessings on that mandolin,” chuckled this industrious young human beaver.  “If it wasn’t for their jolly old twang-twang those Italians might hear my fairy buzz-saw at work.”

Yet, though he progressed, what a fearful length of time this task appeared to take!

“And, if it turns out that there’s another padlock in place on the outside, this will be just another case of love’s labor lose,” sighed the boy.

Occasionally, when the mandolin sounds ceased for a few moments, Benson rested, too.  It would never do to take the risk of having his slight noise overheard.

At last!  The saw went through the ring, proclaiming the task all but finished.  First, with trembling fingers, the submarine boy replaced the saw in its case.  Then, with another tough little tool, he started patiently to bend the severed ends of the ring metal sufficiently far apart.  In this he succeeded finally.

Removing the padlock, he let the hasp fall away from the staple.  On the floor above the mandolin was twanging merrily, the voices of the Italians rising somewhat in their song.